[Dnsmasq-discuss] Ignore single hosts for DHCPv4 but not for DHCPv6/SLAAC, SLAAC name resolution

[Ziggy SpaceRat]

Greetings,

I would like to know if there is any way to achieve this:

While I generally assign IPv4 addresses to all hosts in my network, I
do not want to do this for a few ones (Those that I've already
switched to IP(v6)-only operation).

I know that I can disable DHCP entirely for a specific host using

dhcp-host=00:1d:ec:12:34:56,ignore

but what I want is more like

dhcp-host=00:1d:ec:12:34:56,hostname

-» Gets no IPv4 address and no IPv6 address (as none entered), but the
entry is still used for host name probing in conjunction with SLAAC.

However what this really does is:
Gets a random IPv4 (and/or IPv6) address from the pool(s).


Is there any way I can configure this for *single* hosts?
- DHCPv4 completely disabled
- DHCPv6 announcing DNS server only (Just O flag)
- Still able to resolve name based on SLAAC

For the SLAAC resolution, I know that DNSMasq tries this:
When a DHCP host entry exists, DNSMasq builds the stateless address
this MAC would result in without the bullshit extensions and then
pings that host.

I also see why *this* method can not work for hosts without DHCP
address assigning: DNSMasq doesn't notice *when* they configure their
addresses, as the triggering event (DHCP) is missing.

But I have two different approaches which might work even better:
1. Periodically check the NDP neighbourhood for hosts
and/or
2. Build the stateless address when the host's name gets queried and
ping it (Same method as now, just a different/additional trigger)
Would of course delay the response but it's better than no resolution
at all ...

BTW: Hosts that are configured for DHCPv4 on the host side but are
ignored by DNSMasq are causing terribly high CPU load while they
hammer DNSMasq for a DHCP lease ...